A reckless driver was caught speeding at 122mph by police on a stretch of the A41 on Wednesday night.
Hertfordshire's Roads Policing Unit said road conditions on the night were wet, making it potentially fatal.
A police spokesman said: "The A41 is NOT a race track, and driving at these sorts of speeds is extremely dangerous.
"The driver was reported for driving offences and will have to attend court.
"Please do not speed on the A41, else our Roads Policing Units will catch you."